Răspuns:
[tex] \frac{sinx + 4cosx}{cosx} = 5[/tex]
[tex]sinx + 4cosx = 5cosx[/tex]
[tex]sinx - cosx = 0[/tex]
[tex]sin(x - \frac{\pi}{4} ) = 0[/tex]
[tex]x - \frac{\pi}{4} = k\pi[/tex]
[tex]x = k\pi + \frac{\pi}{4} = > k = 0 = > x = \frac{\pi}{4} = 45 \: de \: grade[/tex]
